Rishi K. Wadhera, M.D., from Harvard Medical School in Boston, and colleagues conducted a retrospective cohort study to examine whether rates of uninsurance, quality of care, and outcomes changed among patients hospitalized for AMI in states that elected to expand Medicaid three years prior versus nonexpansion states. Data were included for 325,343 patients.

The researchers found that from 2012 to 2016, there was a decrease in uninsured AMI hospitalization in expansion states (18.0 to 8.4 percent), with a more modest decrease seen in nonexpansion states (25.6 to 21.1 percent). There was an increase in Medicaid coverage from 7.5 to 14.4 percent in expansion states and from 6.2 to 6.6 percent in nonexpansion states. For low-income patients, in expansion versus nonexpansion states, there was no change in use of most procedures. Similar improvement in in-hospital mortality was seen between expansion and nonexpansion states (3.2 to 2.8 percent versus 3.3 to 3.0 percent; P for interaction = 0.48).

"Among low-income adults hospitalized for AMI, Medicaid expansion was not associated with improved quality of care or better outcomes," the authors write. "These findings suggest that current care systems for urgent, time-sensitive conditions may be less sensitive to insurance than has been recognized in the past."

Several authors disclosed financial ties to the pharmaceutical industry.